Determination of Thiocyanate in Desulfurization Waste Solution by Spectrophotometry

摘要

Affects of thiosulfate (S_2O_3 ~(2-)) and sulfate (SO_4 ~(2-)) on determination of thiocyanate (SCN~-) in desulfurization waste solution (DWS) by spectrophotometry were investigated. The experiment results suggested that S_2O_3 2- and Fe~(3+) generated purple compound [Fe(S_2O_3)_2]~- which has a strong absorption at 450nm, but the purple soon fades in this process. As long as the reacting time is longer than 120s, the impact of S_2O_3 ~(2-) can be eliminated. In addition, sulfate has no effect. At 450nm wavelength, linear relationship between concentration of SCN~- and absorbance was C=19.7272A-0.2774, which conformed to the Beer Law in the range of 2.00 ~ 19.45μg·ml~(-1), the correlation coefficients was 0.9996. The Fe~(3+)-SCN~- spectrophotometric method of monitoring SCNin desulfurization waste solution was feasible.